JERUSALEM, Israel -- Israeli naval officers tracked two fishing boats as they sped toward Egyptian waters from the Gaza Strip and then back again.

On the return trip, the Navy opened fire on the vessels, wounding four people on board and setting off secondary explosions that confirmed the vessels were transporting ammunition and explosives back to Gaza.

The Palestinian Authority's official Ma'an news agency reported the men were fishermen from Gaza, but the IDF Spokesperson's Office said the boats were being used for smuggling weapons.

Gunmen from the Gaza Strip opened fire on the Israeli vessels without injuring anyone. The four "fisherman" were treated for moderate injuries at a hospital in Rafah in the Gaza Strip.